An enlarged heart (cardiomegaly) isn't a disease, but rather a symptom of another condition.

The term "cardiomegaly" most commonly refers to an enlarged heart seen on a chest X-ray. Other tests are then needed to diagnose the condition causing your enlarged heart.

You may develop an enlarged heart temporarily because of a stress on your body, such as pregnancy, or because of a medical condition, such as the weakening of the heart muscle, coronary artery disease, heart valve problems or abnormal heart rhythms.

An enlarged heart may be treatable by correcting the cause. Treatment for an enlarged heart can include medications, medical procedures or surgery.

In some people, an enlarged heart causes no signs or symptoms. Others may have these signs and symptoms:

Shortness of breath

Abnormal heart rhythm (arrhythmia)

Swelling (edema)

When to see a doctor

An enlarged heart is easier to treat when it's detected early, so talk to your doctor if you have concerns about your heart.

If you have new signs or symptoms that might be related to your heart, make an appointment to see your doctor.

Seek emergency medical care if you have any of these signs and symptoms, which may mean you're having a heart attack:

Chest pain

Severe shortness of breath

Fainting

An enlarged heart can be caused by conditions that cause your heart to pump harder than usual or that damage your heart muscle. Sometimes the heart enlarges and becomes weak for unknown reasons (idiopathic).

A heart condition you're born with (congenital), damage from a heart attack or an abnormal heartbeat (arrhythmia) can cause your heart to enlarge. Other conditions associated with an enlarged heart include:

High blood pressure. Your heart may have to pump harder to deliver blood to the rest of your body, enlarging and thickening the muscle.

High blood pressure can cause the left ventricle to enlarge, causing the heart muscle eventually to weaken. High blood pressure may also enlarge the upper chambers of your heart (atria).

Heart valve disease. Four valves in your heart keep blood flowing in the right direction. If the valves are damaged by conditions such as rheumatic fever, a heart defect, infections (infectious endocarditis), connective tissue disorders, certain medications or radiation treatments for cancer, your heart may enlarge.

Disease of the heart muscle (cardiomyopathy). As this thickening and stiffening of heart muscle progresses, your heart may enlarge to try to pump more blood to your body.

High blood pressure in the artery connecting your heart and lungs (pulmonary hypertension). Your heart may need to pump harder to move blood between your lungs and your heart. As a result, the right side of your heart may enlarge.

Fluid around your heart (pericardial effusion). Accumulation of fluid in the sac (pericardium) that contains your heart may cause your heart to appear enlarged on a chest X-ray.

Low red blood cell count (anemia). Anemia is a condition in which there aren't enough healthy red blood cells to carry adequate oxygen to your tissues. Untreated, chronic anemia can lead to a rapid or irregular heartbeat. Your heart must pump more blood to make up for the lack of oxygen in the blood.

Thyroid disorders. Both an underactive thyroid gland (hypothyroidism) and an overactive thyroid gland (hyperthyroidism) can lead to heart problems, including an enlarged heart.

Excessive iron in the body (hemochromatosis). Hemochromatosis is a disorder in which your body doesn't properly metabolize iron, causing it to build up in various organs, including your heart. This can cause an enlarged left ventricle due to weakening of the heart muscle.

Rare diseases that can affect your heart, such as amyloidosis. Amyloidosis is a condition in which abnormal proteins circulate in the blood and may be deposited in the heart, interfering with your heart's function and causing it to enlarge.

You may have a greater risk of developing an enlarged heart if you have any of the following risk factors:

High blood pressure. Having a blood pressure measurement higher than 140/90 millimeters of mercury puts you at an increased risk of developing an enlarged heart.

A family history of enlarged hearts or cardiomyopathy. If an immediate family member, such as a parent or sibling, has had an enlarged heart, you may be more susceptible to developing the condition.

Blocked arteries in your heart (coronary artery disease). With this condition, fatty plaques in your heart arteries obstruct blood flow through your heart vessels, which can lead to a heart attack. When a section of heart muscle dies, your heart has to pump harder to get adequate blood to the rest of your body, causing it to enlarge.

Congenital heart disease. If you're born with a condition that affects the structure of your heart, you may be at risk of developing an enlarged heart.

Valvular heart disease. The heart has four valves — aortic, mitral, pulmonary and tricuspid — that open and close to direct blood flow through your heart. Conditions that damage the valves may cause the heart to enlarge.

The risk of complications from an enlarged heart depends on the part of the heart that is enlarged and the cause.

Complications of enlarged heart can include:

Heart failure. One of the most serious types of enlarged heart, an enlarged left ventricle, increases the risk of heart failure. In heart failure, your heart muscle weakens, and the ventricles stretch (dilate) to the point that the heart can't pump blood efficiently throughout your body.

Blood clots. Having an enlarged heart may make you more susceptible to forming blood clots in the lining of your heart. If clots enter your bloodstream, they can block blood flow to vital organs, even causing a heart attack or stroke. Clots that develop on the right side of your heart may travel to your lungs, a dangerous condition called a pulmonary embolism.

Heart murmur. For people who have an enlarged heart, two of the heart's four valves — the mitral and tricuspid valves — may not close properly because they become dilated, leading to a backflow of blood. This flow creates sounds called heart murmurs. Although not necessarily harmful, heart murmurs should be monitored by your doctor.

Cardiac arrest and sudden death. Some forms of enlarged heart can lead to disruptions in your heart's beating rhythm. Heart rhythms too slow to move blood or too fast to allow the heart to beat properly can result in fainting or, in some cases, cardiac arrest or sudden death.

If you think you may have an enlarged heart or are worried about your heart disease risk because of your family history, make an appointment with your doctor. If you have heart disease, your doctor may refer you to a heart specialist (cardiologist).

Here's some information to help you prepare for your appointment.

What you can do

Be aware of any pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet or fast before tests.

Write down your symptoms, including ones that may seem unrelated to coronary artery disease.

Write down key personal information, including a family history of heart disease, stroke, high blood pressure or diabetes, and major stresses or recent life changes.

Make a list of all medications, vitamins or supplements you're taking.

Take a family member or friend along, if possible. Someone who accompanies you may remember something you missed or forgot.

Write down questions to ask your doctor.

Preparing a list of questions will help you make the most of your time with your doctor. For heart disease, some basic questions to ask your doctor include:

What is likely causing my symptoms or condition?

What are other possible causes for my symptoms or condition?

What tests do I need?

What's the best treatment?

What foods should I eat or avoid?

What's an appropriate level of physical activity?

Are there restrictions I should follow?

How often should I be screened for heart disease? For example, how often do I need a cholesterol test?

I have other health conditions. How can I best manage them together?

Should I see a specialist?

Should my children be screened for this condition?

Is there a generic alternative to the medicine you're prescribing?

Are there brochures or other printed materials I can take? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your doctor is likely to ask you questions, including:

When did your symptoms begin?

Have your symptoms been continuous or occasional?

How severe are your symptoms?

What, if anything, seems to improve your symptoms?

What, if anything, appears to worsen your symptoms?

What is your typical diet?

Do you drink alcohol? How much?

Do you smoke?

Are you physically active? How often do you exercise?

Have you been diagnosed with other conditions?

Do you have a family history of heart disease?

If you have symptoms of a heart problem, your doctor will perform a physical exam and order tests to determine if your heart is enlarged and to find the cause of your condition. These tests may include:

Chest X-ray. X-ray images help your doctor see the condition of your lungs and heart. If your heart is enlarged on an X-ray, other tests will usually be needed to find the cause.

Electrocardiogram.This test records the electrical activity of your heart through electrodes attached to your skin. Impulses are recorded as waves and displayed on a monitor or printed on paper. This test helps your doctor diagnose heart rhythm problems and damage to your heart from a heart attack.

Echocardiogram.This test for diagnosing and monitoring an enlarged heart uses sound waves to produce a video image of your heart. With this test, the four chambers of the heart can be evaluated.

Your doctor can use the results to see how efficiently your heart is pumping, determine which chambers of your heart are enlarged, look for evidence of previous heart attacks and determine if you have congenital heart disease.

Stress test. A stress test, also called an exercise stress test, provides information about how well your heart works during physical activity.

An exercise stress test usually involves walking on a treadmill or riding a stationary bike while your heart rhythm, blood pressure and breathing are monitored.

Cardiac computerized tomography (CT) or magnetic resonance imaging (MRI). In a cardiac CT scan, you lie on a table inside a doughnut-shaped machine called a gantry. An X-ray tube inside the machine rotates around your body and collects images of your heart and chest.

In a cardiac MRI, you lie on a table inside a long tube-like machine that uses a magnetic field and radio waves to produce signals that create images of your heart.

Blood tests. Your doctor may order blood tests to check the levels of certain substances in your blood that may point to a heart problem. Blood tests can also help your doctor rule out other conditions that may cause your symptoms.

Cardiac catheterization and biopsy. In this procedure, a thin tube (catheter) is inserted in your groin and threaded through your blood vessels to your heart, where a small sample (biopsy) of your heart, if indicated, can be extracted for laboratory analysis.

Pressure within the chambers of your heart can be measured to see how forcefully blood pumps through your heart. Pictures of the arteries of the heart can be taken during the procedure (coronary angiogram) to ensure that you don't have a blockage.

Treatments for an enlarged heart focus on correcting the cause.

Medications

If cardiomyopathy or another type of heart condition is to blame for your enlarged heart, your doctor may recommend medications. These may include:

Diuretics to lower the amount of sodium and water in your body, which can help lower the pressure in your arteries and heart

Angiotensin receptor blockers (ARBs) to provide the benefits of ACE inhibitors for those who can't take ACE inhibitors

Beta blockers to lower blood pressure and improve heart function

Digoxin to help improve the pumping function of your heart and lessen the need for hospitalization for heart failure

Anticoagulants to reduce the risk of blood clots that could cause a heart attack or stroke

Anti-arrhythmics to keep your heart beating with a normal rhythm

Medical procedures and surgeries

If medications aren't enough to treat your enlarged heart, medical procedures or surgery may be necessary.

Medical devices to regulate your heartbeat. For a certain type of enlarged heart (dilated cardiomyopathy), a pacemaker that coordinates the contractions between the left and right ventricle may be necessary. In people who may be at risk of serious arrhythmias, drug therapy or an implantable cardioverter-defibrillator (ICD) may be an option.

ICDs are small devices — about the size of a pager — implanted in your chest to continuously monitor your heart rhythm and deliver electrical shocks when needed to control abnormal, rapid heartbeats. The devices can also work as pacemakers.

If the main cause of your enlarged heart is atrial fibrillation, then you may need procedures to return your heart to regular rhythm or to keep your heart from beating too quickly.

Heart valve surgery. If your enlarged heart is caused by a problem with one of your heart valves, you may have surgery to remove the valve and replace it with either an artificial valve or a tissue valve from a pig, cow or deceased human donor. If blood leaks backward through your valve (valve regurgitation), the leaky valve may be surgically repaired or replaced.

Left ventricular assist device (LVAD). If you have heart failure, you may need this implantable mechanical pump to help your weakened heart pump. You may have an LVAD implanted while you wait for a heart transplant or, if you're not a heart transplant candidate, as a long-term treatment for heart failure.

Heart transplant. If medications can't control your symptoms, a heart transplant may be a final option. Because of the shortage of donor hearts, even people who are critically ill may have a long wait before having a heart transplant.

There are ways to improve your condition, even though you can't cure it. Your doctor may recommend the following lifestyle changes:

Quit smoking.

Lose excess weight.

Limit salt in your diet.

Control diabetes.

Monitor your blood pressure.

Get modest exercise, after discussing with your doctor the most appropriate program of physical activity.

Avoid or eliminate alcohol and caffeine.

Try to sleep eight hours nightly.

Tell your doctor if you have a family history of conditions that can cause an enlarged heart, such as cardiomyopathy. If cardiomyopathy or other heart conditions are diagnosed early, treatments may prevent the disease from worsening.

You can help reduce your chance of developing heart failure by eating a healthy diet and not abusing alcohol or cocaine. Controlling high blood pressure with diet, exercise and possibly medications also prevents many people who have an enlarged heart from developing heart failure.

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